As electronic components are getting smaller and smaller along with the internal structures in integrated circuits, it is getting easier to either completely destroy or otherwise impair electronic components. In particular, many integrated circuits are highly susceptible to damage from the discharge of static electricity. Generally, electrostatic discharge (ESD) is the transfer of an electrostatic charge between bodies at different electrostatic potentials (voltages), caused by direct contact or induced by an electrostatic field. The discharge of static electricity, or ESD, has become a critical problem for the electronics industry.
When an ESD pulse occurs on a transistor, the extremely high voltage of the ESD pulse can break down the transistor and can potentially cause permanent damage. Consequently, the circuits associated with the input/output pads of an integrated circuit need to be protected from ESD pulses so that they are not damaged.
Device failures that result from ESD events are not always immediately catastrophic or apparent. Often, the device is only slightly weakened but is less able to withstand normal operating stresses and, hence, may result in a reliability problem. Therefore, various ESD protection circuits should be included in the device to protect the various components.
ESD protection devices are designed based on the type of component that is being protected. However, designing ESD protection devices for high voltage components requires overcoming a number of limitations imposed by the need to reduce the device area without reducing the required high voltage protection.